Quality assurance & pharmacopeial assay

Question 1

What are the sources of impurities?

Answer 1

1. Raw materials
2. Method of manufacture
3. Atmospheric contaminant
4. Manufacturing hazards
5. Inadequate storage

Question 2

Sources of impurities in method of manufacture

Answer 2

1. Reagents employed in process
2. Reagents added to remove other impurities
3. Solvents
4. Reaction vessels

Question 3

Sources of impurities in manufacturing hazards

Answer 3

1. Particulate contamination
2. Process errors
3. Cross-contamination
4. Microbial contamination
5. Packing errors

Question 4

Sources of impurities in inadequate storage

Answer 4

1. Filth
2. Chemical instability
   3, Reaction with container materials
3. Physical changes
4. Temperature effects

Question 5

What are limit tests?

Answer 5

Quantitative or semi-quantitative tests designed to identify and control small quantities of impurity
which may be present in the drug substance

Question 6

Comparison methods

Answer 6

A standard containing a definite amount of impurity
is set up at the same time and same conditions as the test experiment.

Question 7

Official limits for which impurities are based on comparison methods?

Answer 7

Chloride
Sulphates
Iron
Heavy metals

Question 8

Total Ash method

Answer 8

A measure of the total ash remaining after incineration

Question 9

What does high ash value indicate?

Answer 9

Contamination, substitution or carelessness in preparing the crude drugs for marketing Inorganic salts of carbonates, phosphate or silicates of sodium, potassium calcium and magnesium

Question 10

Infrared Absorption Test for identification

Answer 10

Compare the IR spectrum of the test sample and the USP reference standard

Question 11

Types of limit tests

Answer 11

a. Limits of insoluble matter
b. Limits of soluble matters
c. Limits of moisture, volatile matters, and residual solvents
d. Limits of non-volatile matter
e. Loss on ignition
- Limits of residue on ignition
- Ash values
e. Precipitation methods

Question 12

What is the significance of IR spectrum?

Answer 12

Stretching and bending of bonds in different functional groups to the structure of the analyte

Question 13

UV Absorption Test for identification

Answer 13

UV absorption measured of a test solution and a standard solution, using a 1cm cell, over 200-400nm

Question 14

Significance of UV spectra

Answer 14

1. Determine the absorptivities and or absorbance ratios as indicated in the monograph
   - The requirements are met if the UV absorption spectra of the test and standard solutions exhibit maxima and minima at the same wavelength and the absorptivities and/or absorbance ratios are within specified limits.

Question 15

TLC Test for identification

Answer 15

The Rf value of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution – indicates a positive identity to the Standard reference

Question 16

Advantages of Titrimetric analysis

Answer 16

1. Capable of high degree of precision and accuracy
2. Methods are generally robust
3. Analyses can be automated and cheap to perform

Question 17

Limitations of Titrimetric analysis

Answer 17

1. Method may not be selective
2. Time-consuming
3. Require large amount s of sample and reagents

Question 18

Types of Titrimetric analysis

Answer 18

1. Direct acid/base titration in aqueous phase
2. Indirect titration in aqueous phase
3. Argentometric titration
4. Complexometric titration
5. Redox Titration
6. Non-aqueous Titration
7. Potentiometric Titration

Question 19

What are primary standards

Answer 19

Stable chemical compounds that are available in high purity and that can be used to standardize the standard solutions used in titrations

Question 20

What is used to determine correction factor?

Answer 20

Primary standards

Question 21

Correction factor

Answer 21

Ratio of (Actual concentration)/(Desired (or nominal)concentration).

Question 22

What does the value of correction factor signifies?

Answer 22

f < 1: the prepared solution is of lower concentration that what was desired
f > 1: the prepared solution is of higher concentration that what was desired
f = 1: the prepared solution is prepared precisely to the desired

Question 23

When is indirect (back) titration used?

Answer 23

a) Volatile substance (e.g. ammonia, volatile oil)
b) Insoluble substances (e.g. CaCO3)
c) Substances for which a quantitative reaction proceeds rapidly only in excess of a reagent (e.g. lactic acid)
d) Substances which require heating with a volumetric reagent during the determination in which a decomposition or loss of the reactants or products would occur in the process (e.g. aspirin)

Question 24

What is necessary during back titration involving heating a liquid containing excess of standard alkali,
cooling and back titrate the excess.

Answer 24

Blank titration - heating and cooling may cause apparent changes in strength of excess reagent

Question 25

HPLC analysis always requires a _________.

Answer 25

Calibration curve

Question 26

(HPLC) Calibration against internal standard which should _____?

Answer 26

1. Be closely related in structure to the analyse
2. Be stable
3. Be chromo

Question 27

QA vs QC

Answer 27

1. QA is proactive, QC results in reactive steps to correct issue
2. QA is process oriented, QC is product oriented
3. QA controls overall (at system level), QC controls parts in the process
4. QA activities create high quality products, QC verifies products in post-manufacture stage
5. QA involves entire team, QC by dedicated trained personnel

Question 28

5 key components of GMP (1)

Answer 28

Raw/starting materials used in manufacturing must be pure.

Question 29

5 key components of GMP (2)

Answer 29

Premises and equipment used for manufacturing must be maintained for operational readiness.

Question 30

5 key components of GMP (3)

Answer 30

People involved in the manufacturing process must be trained to competent level.

Question 31

5 key components of GMP (4)

Answer 31

The manufacturing procedures must use the latest technology and science.

Question 32

5 key components of GMP (5)

Answer 32

Processes must be documented to show compliance.